Kendo UI for jQuery
The Kendo UI for jQuery Validator component is convenient library for validating form inputs. It supports a variety of built-in validation rules and provides a convenient way for setting custom-rule handling.
The jQuery Validator component includes default rules for virtually any common scenario. When you have business rules that are out of the ordinary, you can write your own.
The Validator provides a tooltip to help users pinpoint the spot where the error happened. This is essentially a popup that you can control its position relative to the target.
The Validator can group all issues with your form data in one place. Putting all messages in the same place makes it easy to identify that something went wrong (because the user sees a big red blob).